The Pueblo San Diego watershed is the smallest hydrologic unit (HU) in San Diego County, encompassing approximately 60 square miles of predominantly urban landscape in the cities of San Diego, La Mesa, Lemon Grove, and National City.  The watershed contains the smallest proportion of unincorporated area (0.3%) of the HUs within the county.  The population of the Pueblo San Diego watershed is approximately 500,000 residents, making it the county’s most densely populated watershed.  Approximately 75% of the watershed is developed.  Residential, retail/ office, and industrial land uses account for 45%, 11%, and 10% of the total, respectively.  In addition, there are relatively large percentages of land used for transportation corridors and highways.   Due to the high level of existing urbanization in the watershed, only small amounts of additional land is projected for development over the next 15 years.

The beneficial uses of the inland surface waters in the Pueblo San Diego watershed are limited to contact (potential use) and non-contact recreation, warm freshwater habitat, and wildlife habitat.   The San Diego Bay receiving water supports an extensive array of beneficial uses (see table below).

The watershed drainage consists of a group of relatively small local creeks and pipe conveyances, many of which are concrete-lined and drain directly into San Diego Bay.  The creeks in the watershed are highly impacted by urban runoff, and Chollas Creek and the mouth of the creek in San Diego Bay are listed as 303(d)-impaired water bodies for various trace metals parameters and aquatic toxicity.  Five sites in San Diego Bay that are impacted by runoff from the Pueblo San Diego watershed have been identified as hot spots by California’s Bay Protection Toxic Cleanup Program.

Beneficial water uses within the Pueblo Watershed as designated in the State Water Resources Control Board's San Diego Region Basin Plan.